How Alan Parsons Engineered the Quadrophonic Mix of Dark Side of the Moon with the EMI SQ System

That helicopter pan on “On the Run” didn’t just happen. Alan Parsons used the EMI SQ (Stereo Quadraphonic) encoding system to create a full 360-degree soundfield for The Dark Side of the Moon — one of the first rock albums mixed in quad. SQ used phase shifts to embed four channels into two stereo tracks, which a special decoder could unfold into four speakers. Parsons had to pre-plan every pan because quad mixing required separate busses on the EMI TG12345 desk at Abbey Road.

For the helicopter on “On the Run,” Parsons used two specific techniques. First, he bounced a recorded helicopter sound between the front left and front right speakers using manual pan pots, then repeated the same pattern but reversed for the rear channels to create a circular motion. Second, he vari-speeded the tape machine during the bounce-down, so the rotor rhythm would speed up and slow down as it circled the listener. The result is that iconic spinning effect that feels like the helicopter is orbiting your head, not just moving left to right. No automation – all done by hand on the faders.